Owasys 4x is based on a Debian 8 "Jessie" release.
It's a full Linux and as such apt-get can be used to retrieve ARM packages.
The thing is that the internal antenna of the WiFi-BT module goes at the front of the unit, in the down side, and therefore it is better to install the unit in a way in that this part is free of metallic barriers.
Here in this picture the position of the internal antenna is shown:
As you can see, the antenna is placed in the side where the optional internal GNSS antenna is also placed, so this "UP" mark can be taken to know which place to set upwards when installing the unit, or without metallic parts just in front of it. Please forward this information to your customer, so that they can retest the Bluetooth functionality again after placing the unit with a better view of the antenna.
We will include this Information in the next release of the Integrators Manual.